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nuttx/arch/arm/src/armv7-a/arm_syscall.c
wangbowen6 4859d40a51 arm_syscall: add SYS_save_context for armv7-a 
I noticed that there is not register information in the crash log
when DEBUGASSERT failed, the reason is that the arm_dumpstate()
call up_saveusercontext() to get the context of current task but
armv7-a do not support syscall SYS_save_context.

crash log:
[48/12/ 7 16:14:03] [CPU1] [10] [a7] up_assert: Assertion failed CPU1 at file:mm_heap/mm_free.c line: 115 task: panel_apps
[48/12/ 7 16:14:03] [CPU1] [10] [a7] backtrace|10: 0x38443440 0x38081f30 0x38002888 0x3802cb7c 0x38036e34 0x38037978 0x380386f0 0x38037e64
[48/12/ 7 16:14:03] [CPU1] [10] [a7] backtrace|10: 0x38036edc 0x380376a0 0x38035a2c 0x380070d0 0x3804eae4 0x3802abd0 0x3802277c 0x3804b998
[48/12/ 7 16:14:03] [CPU1] [10] [a7] backtrace|10: 0x38091be8 0x38099250 0x38096adc 0x3808f134 0x3802d5d8 0x380191a4
[48/12/ 7 16:14:03] [CPU1] [10] [a7] arm_registerdump: R0: 00000000 R1: 00000000 R2: 00000000  R3: 00000000
[48/12/ 7 16:14:03] [CPU1] [10] [a7] arm_registerdump: R4: 00000000 R5: 00000000 R6: 00000000  R7: 00000000
[48/12/ 7 16:14:03] [CPU1] [10] [a7] arm_registerdump: R8: 00000000 SB: 00000000 SL: 00000000  FP: 00000000
[48/12/ 7 16:14:03] [CPU1] [10] [a7] arm_registerdump: IP: 00000000 SP: 00000000 LR: 00000000  PC: 00000000
[48/12/ 7 16:14:03] [CPU1] [10] [a7] arm_registerdump: CPSR: 00000000

Signed-off-by: wangbowen6 <wangbowen6@xiaomi.com>
2022-12-04 01:52:49 +08:00

602 lines
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/****************************************************************************
* arch/arm/src/armv7-a/arm_syscall.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <inttypes.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <debug.h>
#include <syscall.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/addrenv.h>
#include "addrenv.h"
#include "arm.h"
#include "arm_internal.h"
#include "group/group.h"
#include "signal/signal.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: dump_syscall
*
* Description:
* Dump the syscall registers
*
****************************************************************************/
static void dump_syscall(const char *tag, uint32_t cmd, const uint32_t *regs)
{
/* The SVCall software interrupt is called with R0 = system call command
* and R1..R7 = variable number of arguments depending on the system call.
*/
#ifdef CONFIG_LIB_SYSCALL
if (cmd >= CONFIG_SYS_RESERVED)
{
svcinfo("SYSCALL %s: regs: %p cmd: %" PRId32 " name: %s\n", tag,
regs, cmd, g_funcnames[cmd - CONFIG_SYS_RESERVED]);
}
else
#endif
{
svcinfo("SYSCALL %s: regs: %p cmd: %" PRId32 "\n", tag, regs, cmd);
}
svcinfo(" R0: %08" PRIx32 " %08" PRIx32 " %08" PRIx32 " %08" PRIx32
" %08" PRIx32 " %08" PRIx32 " %08" PRIx32 " %08" PRIx32 "\n",
regs[REG_R0], regs[REG_R1], regs[REG_R2], regs[REG_R3],
regs[REG_R4], regs[REG_R5], regs[REG_R6], regs[REG_R7]);
svcinfo(" R8: %08" PRIx32 " %08" PRIx32 " %08" PRIx32 " %08" PRIx32
" %08" PRIx32 " %08" PRIx32 " %08" PRIx32 " %08" PRIx32 "\n",
regs[REG_R8], regs[REG_R9], regs[REG_R10], regs[REG_R11],
regs[REG_R12], regs[REG_R13], regs[REG_R14], regs[REG_R15]);
svcinfo("CPSR: %08" PRIx32 "\n", regs[REG_CPSR]);
}
/****************************************************************************
* Name: dispatch_syscall
*
* Description:
* Call the stub function corresponding to the system call. NOTE the non-
* standard parameter passing:
*
* R0 = SYS_ call number
* R1 = parm0
* R2 = parm1
* R3 = parm2
* R4 = parm3
* R5 = parm4
* R6 = parm5
*
* The values of R4-R5 may be preserved in the proxy called by the user
* code if they are used (but otherwise will not be).
*
* WARNING: There are hard-coded values in this logic!
*
* Register usage:
*
* R0 - Need not be preserved.
* R1-R3 - Need to be preserved until the stub is called. The values of
* R0 and R1 returned by the stub must be preserved.
* R4-R11 must be preserved to support the expectations of the user-space
* callee. R4-R6 may have been preserved by the proxy, but don't know
* for sure.
* R12 - Need not be preserved
* R13 - (stack pointer)
* R14 - Need not be preserved
* R15 - (PC)
*
****************************************************************************/
#ifdef CONFIG_LIB_SYSCALL
static void dispatch_syscall(void) naked_function;
static void dispatch_syscall(void)
{
__asm__ __volatile__
(
" sub sp, sp, #16\n" /* Create a stack frame to hold 3 parms + lr */
" str r4, [sp, #0]\n" /* Move parameter 4 (if any) into position */
" str r5, [sp, #4]\n" /* Move parameter 5 (if any) into position */
" str r6, [sp, #8]\n" /* Move parameter 6 (if any) into position */
" str lr, [sp, #12]\n" /* Save lr in the stack frame */
" ldr ip, =g_stublookup\n" /* R12=The base of the stub lookup table */
" ldr ip, [ip, r0, lsl #2]\n" /* R12=The address of the stub for this SYSCALL */
" blx ip\n" /* Call the stub (modifies lr) */
" ldr lr, [sp, #12]\n" /* Restore lr */
" add sp, sp, #16\n" /* Destroy the stack frame */
" mov r2, r0\n" /* R2=Save return value in R2 */
" mov r0, %0\n" /* R0=SYS_syscall_return */
" svc %1\n"::"i"(SYS_syscall_return),
"i"(SYS_syscall) /* Return from the SYSCALL */
);
}
#endif
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: arm_syscall
*
* Description:
* SVC interrupts will vector here with insn=the SVC instruction and
* xcp=the interrupt context
*
* The handler may get the SVC number be de-referencing the return
* address saved in the xcp and decoding the SVC instruction
*
****************************************************************************/
uint32_t *arm_syscall(uint32_t *regs)
{
uint32_t cmd;
#ifdef CONFIG_BUILD_KERNEL
uint32_t cpsr;
#endif
/* Nested interrupts are not supported */
DEBUGASSERT(CURRENT_REGS == NULL);
/* Current regs non-zero indicates that we are processing an interrupt;
* CURRENT_REGS is also used to manage interrupt level context switches.
*/
CURRENT_REGS = regs;
/* The SYSCALL command is in R0 on entry. Parameters follow in R1..R7 */
cmd = regs[REG_R0];
/* The SVCall software interrupt is called with R0 = system call command
* and R1..R7 = variable number of arguments depending on the system call.
*/
dump_syscall("Entry", cmd, regs);
/* Handle the SVCall according to the command in R0 */
switch (cmd)
{
/* R0=SYS_syscall_return: This a SYSCALL return command:
*
* void arm_syscall_return(void);
*
* At this point, the following values are saved in context:
*
* R0 = SYS_syscall_return
*
* We need to restore the saved return address and return in
* unprivileged thread mode.
*/
#ifdef CONFIG_LIB_SYSCALL
case SYS_syscall_return:
{
struct tcb_s *rtcb = nxsched_self();
int index = (int)rtcb->xcp.nsyscalls - 1;
/* Make sure that there is a saved SYSCALL return address. */
DEBUGASSERT(index >= 0);
/* Setup to return to the saved SYSCALL return address in
* the original mode.
*/
regs[REG_PC] = rtcb->xcp.syscall[index].sysreturn;
#ifdef CONFIG_BUILD_KERNEL
regs[REG_CPSR] = rtcb->xcp.syscall[index].cpsr;
#endif
/* The return value must be in R0-R1. dispatch_syscall()
* temporarily moved the value for R0 into R2.
*/
regs[REG_R0] = regs[REG_R2];
#ifdef CONFIG_ARCH_KERNEL_STACK
/* If this is the outermost SYSCALL and if there is a saved user
* stack pointer, then restore the user stack pointer on this
* final return to user code.
*/
if (index == 0 && rtcb->xcp.ustkptr != NULL)
{
regs[REG_SP] = (uint32_t)rtcb->xcp.ustkptr;
rtcb->xcp.ustkptr = NULL;
}
#endif
/* Save the new SYSCALL nesting level */
rtcb->xcp.nsyscalls = index;
/* Handle any signal actions that were deferred while processing
* the system call.
*/
rtcb->flags &= ~TCB_FLAG_SYSCALL;
nxsig_unmask_pendingsignal();
}
break;
#endif
/* R0=SYS_save_context: This is a save context command:
*
* int up_saveusercontext(void *saveregs);
*
* At this point, the following values are saved in context:
*
* R0 = SYS_save_context
* R1 = saveregs
*
* In this case, we simply need to copy the current registers to the
* save register space references in the saved R1 and return.
*/
case SYS_save_context:
{
DEBUGASSERT(regs[REG_R1] != 0);
memcpy((uint32_t *)regs[REG_R1], regs, XCPTCONTEXT_SIZE);
}
break;
/* R0=SYS_restore_context: Restore task context
*
* void arm_fullcontextrestore(uint32_t *restoreregs)
* noreturn_function;
*
* At this point, the following values are saved in context:
*
* R0 = SYS_restore_context
* R1 = restoreregs
*/
case SYS_restore_context:
{
/* Replace 'regs' with the pointer to the register set in
* regs[REG_R1]. On return from the system call, that register
* set will determine the restored context.
*/
CURRENT_REGS = (uint32_t *)regs[REG_R1];
DEBUGASSERT(CURRENT_REGS);
}
break;
/* R0=SYS_switch_context: This a switch context command:
*
* void arm_switchcontext(uint32_t **saveregs,
* uint32_t *restoreregs);
*
* At this point, the following values are saved in context:
*
* R0 = SYS_switch_context
* R1 = saveregs
* R2 = restoreregs
*
* In this case, we do both: We save the context registers to the save
* register area reference by the saved contents of R1 and then set
* regs to the save register area referenced by the saved
* contents of R2.
*/
case SYS_switch_context:
{
DEBUGASSERT(regs[REG_R1] != 0 && regs[REG_R2] != 0);
*(uint32_t **)regs[REG_R1] = regs;
CURRENT_REGS = (uint32_t *)regs[REG_R2];
}
break;
/* R0=SYS_task_start: This a user task start
*
* void up_task_start(main_t taskentry, int argc, char *argv[])
* noreturn_function;
*
* At this point, the following values are saved in context:
*
* R0 = SYS_task_start
* R1 = taskentry
* R2 = argc
* R3 = argv
*/
#ifdef CONFIG_BUILD_KERNEL
case SYS_task_start:
{
/* Set up to return to the user-space _start function in
* unprivileged mode. We need:
*
* R0 = argc
* R1 = argv
* PC = taskentry
* CSPR = user mode
*/
regs[REG_PC] = regs[REG_R1];
regs[REG_R0] = regs[REG_R2];
regs[REG_R1] = regs[REG_R3];
cpsr = regs[REG_CPSR] & ~PSR_MODE_MASK;
regs[REG_CPSR] = cpsr | PSR_MODE_USR;
}
break;
#endif
/* R0=SYS_pthread_start: This a user pthread start
*
* void up_pthread_start(pthread_startroutine_t entrypt,
* pthread_addr_t arg) noreturn_function;
*
* At this point, the following values are saved in context:
*
* R0 = SYS_pthread_start
* R1 = entrypt
* R2 = arg
*/
#if !defined(CONFIG_BUILD_FLAT) && !defined(CONFIG_DISABLE_PTHREAD)
case SYS_pthread_start:
{
/* Set up to enter the user-space pthread start-up function in
* unprivileged mode. We need:
*
* R0 = entrypt
* R1 = arg
* PC = startup
* CSPR = user mode
*/
regs[REG_PC] = regs[REG_R1];
regs[REG_R0] = regs[REG_R2];
regs[REG_R1] = regs[REG_R3];
cpsr = regs[REG_CPSR] & ~PSR_MODE_MASK;
regs[REG_CPSR] = cpsr | PSR_MODE_USR;
}
break;
#endif
#ifdef CONFIG_BUILD_KERNEL
/* R0=SYS_signal_handler: This a user signal handler callback
*
* void signal_handler(_sa_sigaction_t sighand, int signo,
* siginfo_t *info, void *ucontext);
*
* At this point, the following values are saved in context:
*
* R0 = SYS_signal_handler
* R1 = sighand
* R2 = signo
* R3 = info
* ucontext (on the stack)
*/
case SYS_signal_handler:
{
struct tcb_s *rtcb = nxsched_self();
/* Remember the caller's return address */
DEBUGASSERT(rtcb->xcp.sigreturn == 0);
rtcb->xcp.sigreturn = regs[REG_PC];
/* Set up to return to the user-space trampoline function in
* unprivileged mode.
*/
regs[REG_PC] = (uint32_t)ARCH_DATA_RESERVE->ar_sigtramp;
cpsr = regs[REG_CPSR] & ~PSR_MODE_MASK;
regs[REG_CPSR] = cpsr | PSR_MODE_USR;
/* Change the parameter ordering to match the expectation of struct
* userpace_s signal_handler.
*/
regs[REG_R0] = regs[REG_R1]; /* sighand */
regs[REG_R1] = regs[REG_R2]; /* signal */
regs[REG_R2] = regs[REG_R3]; /* info */
regs[REG_R3] = regs[REG_R4]; /* ucontext */
#ifdef CONFIG_ARCH_KERNEL_STACK
/* If we are signalling a user process, then we must be operating
* on the kernel stack now. We need to switch back to the user
* stack before dispatching the signal handler to the user code.
* The existence of an allocated kernel stack is sufficient
* information to make this decision.
*/
if (rtcb->xcp.kstack != NULL)
{
DEBUGASSERT(rtcb->xcp.kstkptr == NULL &&
rtcb->xcp.ustkptr != NULL);
rtcb->xcp.kstkptr = (uint32_t *)regs[REG_SP];
regs[REG_SP] = (uint32_t)rtcb->xcp.ustkptr;
}
#endif
}
break;
#endif
#ifdef CONFIG_BUILD_KERNEL
/* R0=SYS_signal_handler_return: This a user signal handler callback
*
* void signal_handler_return(void);
*
* At this point, the following values are saved in context:
*
* R0 = SYS_signal_handler_return
*/
case SYS_signal_handler_return:
{
struct tcb_s *rtcb = nxsched_self();
/* Set up to return to the kernel-mode signal dispatching logic. */
DEBUGASSERT(rtcb->xcp.sigreturn != 0);
regs[REG_PC] = rtcb->xcp.sigreturn;
cpsr = regs[REG_CPSR] & ~PSR_MODE_MASK;
regs[REG_CPSR] = cpsr | PSR_MODE_SYS;
rtcb->xcp.sigreturn = 0;
#ifdef CONFIG_ARCH_KERNEL_STACK
/* We must enter here be using the user stack. We need to switch
* to back to the kernel user stack before returning to the kernel
* mode signal trampoline.
*/
if (rtcb->xcp.kstack != NULL)
{
DEBUGASSERT(rtcb->xcp.kstkptr != NULL &&
(uint32_t)rtcb->xcp.ustkptr == regs[REG_SP]);
regs[REG_SP] = (uint32_t)rtcb->xcp.kstkptr;
rtcb->xcp.kstkptr = NULL;
}
#endif
}
break;
#endif
/* This is not an architecture-specific system call. If NuttX is built
* as a standalone kernel with a system call interface, then all of the
* additional system calls must be handled as in the default case.
*/
default:
{
#ifdef CONFIG_LIB_SYSCALL
struct tcb_s *rtcb = nxsched_self();
int index = rtcb->xcp.nsyscalls;
/* Verify that the SYS call number is within range */
DEBUGASSERT(cmd >= CONFIG_SYS_RESERVED && cmd < SYS_maxsyscall);
/* Make sure that there is a no saved SYSCALL return address. We
* cannot yet handle nested system calls.
*/
DEBUGASSERT(index < CONFIG_SYS_NNEST);
/* Setup to return to dispatch_syscall in privileged mode. */
rtcb->xcp.syscall[index].sysreturn = regs[REG_PC];
#ifdef CONFIG_BUILD_KERNEL
rtcb->xcp.syscall[index].cpsr = regs[REG_CPSR];
#endif
regs[REG_PC] = (uint32_t)dispatch_syscall;
#ifdef CONFIG_BUILD_KERNEL
cpsr = regs[REG_CPSR] & ~PSR_MODE_MASK;
regs[REG_CPSR] = cpsr | PSR_MODE_SYS;
#endif
/* Offset R0 to account for the reserved values */
regs[REG_R0] -= CONFIG_SYS_RESERVED;
/* Indicate that we are in a syscall handler. */
rtcb->flags |= TCB_FLAG_SYSCALL;
#ifdef CONFIG_ARCH_KERNEL_STACK
/* If this is the first SYSCALL and if there is an allocated
* kernel stack, then switch to the kernel stack.
*/
if (index == 0 && rtcb->xcp.kstack != NULL)
{
rtcb->xcp.ustkptr = (uint32_t *)regs[REG_SP];
regs[REG_SP] = (uint32_t)rtcb->xcp.kstack +
ARCH_KERNEL_STACKSIZE;
}
#endif
/* Save the new SYSCALL nesting level */
rtcb->xcp.nsyscalls = index + 1;
#else
svcerr("ERROR: Bad SYS call: 0x%" PRIx32 "\n", regs[REG_R0]);
#endif
}
break;
}
#ifdef CONFIG_ARCH_ADDRENV
/* Check for a context switch. If a context switch occurred, then
* CURRENT_REGS will have a different value than it did on entry. If an
* interrupt level context switch has occurred, then establish the correct
* address environment before returning from the interrupt.
*/
if (regs != CURRENT_REGS)
{
/* Make sure that the address environment for the previously
* running task is closed down gracefully (data caches dump,
* MMU flushed) and set up the address environment for the new
* thread at the head of the ready-to-run list.
*/
group_addrenv(NULL);
}
#endif
/* Restore the cpu lock */
if (regs != CURRENT_REGS)
{
restore_critical_section();
regs = (uint32_t *)CURRENT_REGS;
}
/* Report what happened */
dump_syscall("Exit", cmd, regs);
/* Set CURRENT_REGS to NULL to indicate that we are no longer in an
* interrupt handler.
*/
CURRENT_REGS = NULL;
/* Return the last value of curent_regs. This supports context switches
* on return from the exception. That capability is only used with the
* SYS_context_switch system call.
*/
return regs;
}
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